We tested how two of the most popular cameras match up on exposure, noise, color fidelity and more.

Given all the buzz around RED’s new Helium sensor, we decided to put it to the test against one of its biggest competitors, the ARRI Alexa, in a variety of real-world lighting set-ups in which we could push both sensors to their limits and compare them at different extremes.

Note that this is a test specifically comparing the RED Epic-W camera with the new Helium sensor to the ARRI Alexa Mini with the Alev sensor. This is not meant to be a general “RED vs. ARRI” test, as there are other configurations of RED’s sensors that have been demonstrating very impressive dynamic range and image quality results, including the Weapon Helium, and the Vista Vision Dragon, which we did not look at in this specific test.

Before we dive in, some technical info:

Tech stats

The ARRI Alexa Mini was shot in 3.4k Open Gate ARRIRaw mode recording to C-fast cards, while the RED Epic-W Redcode Raw footage was shot at 8KHD with a 6:1 compression. This was selected because it was the lowest possible compression we could attain with the 240GB RED Mags we were recording to. It’s worth mentioning that with the 1TB high speed RED Mags, it is possible to shoot 8KFF at 6:1 compression on the Epic-W. The Epic-W was also equipped with the Standard OLPF for the purposes of this test.

Unless noted on the clips, both cameras were set to a color temperature of 4000K as a mid-point between their ideal color temperatures, and were shot at ISO 800. In our testing, we found that the Helium’s native ISO was probably closer to ISO 1280, but decided to match both cameras to 800 for the ease of comparison. All footage was shot on 25mm, 35mm and 50mm Leica Summicron-C lenses, at varying T-stops. We utilized a variety of units for lighting, including a pair of Digital Sputnik DS-1 heads as our main units, but also incandescent bulbs, practical lamps, candles, and natural daylight.

For post, we performed a one-light grade on the footage with Alan Gordon from Post Pro Gumbo; no secondary grades were performed. The Alexa footage was debayered into a Log-C gamma space and then graded based on a Rec709 LUT, with slight modifications. Alan noted the IPP2 and the Helium post-pipeline is still a work-in-progress, which makes it a bit difficult to compare to the Alexa, whose post pipeline has been tried and true and unchanged for many years now–but we still thought it would be pertinent to compare, as both cameras are currently on the market.

Colorist Alan Gordon at work.

For the Helium footage, we used RED’s new image processing pipeline, IPP2, and debayered the footage into a Log3G10 gamma space, which was then graded based on the IPP Preview 2 LUT. During testing, we discovered that the previous standard Log space for RED footage, RedLogFilm, was a much closer match to Log-C in terms of brightness and exposure. From our observations, Log3G10 didn’t actually demonstrate a particular advantage over RedLogFilm in terms of highlight retention, despite it being designed for that purpose. Instead, Log3G10 seems to just pull the overall exposure of the image down by about a half stop, and creates slightly smoother rolloff in the shoulder.

The Alexa has at least a stop and half more dynamic range in the highlights when compared to the Helium.

Despite this, we decided to stick to RED’s recommended workflow for Helium for the purposes of this test, while acknowledging that it is a work in progress. We should mention that we edited and colored this footage a month after the first version of IPP2 was released and a few weeks before the latest iteration of IPP2 came out.

Test 1: Overexposure and dynamic range in highlights

In our first test, we wanted to push the sensors to the upper limit of their dynamic ranges, and see how much information could be retained in the highlights and brought back down to “neutral” exposure in the grade. We determined our “neutral” exposure of the subject’s face with our key light measured at an F/2.8 to be at 60IRE, and graded the overexposed shots back down to match that value. In each subsequent shot, we increased the brightness of the key light by one stop, until we capped out at +5 stops overexposure from our base exposure (T/2 on the lens).

In the test results, it is evident that the Alexa has at least a stop and half more dynamic range in the highlights when compared to the Helium. At four stops overexposure, the Alexa footage could be graded back down to 60IRE without losing any information in the highlight at all. At the same stop, the Helium footage begins to clip and lose data that cannot be retrieved or graded back to match. The cutoff is pretty sudden—at three stops overexposure, the Helium footage could still be perfectly matched to the base exposure, but at four, the information is already lost. Notice the information loss in the bare bulb as well in the Helium footage compared the Alexa, which retains more detail in the filament.

At five stops overexposure, the Alexa footage begins to clip in the most overexposed regions of the subject’s face. The Helium footage has total information loss in, and sharp falloff from, overexposed regions. The Alexa also seems to retain more color detail in the overexposed regions, so when they are graded down, the skin tone still maintains its color. In the overexposed regions of the Helium image, color information is lost, and the result when graded down is a very washed-out look.

Test 2: Underexposure and noise

In the second test, we set out to examine the cameras' performances at the opposite extreme: low light scenarios. Our subject was lit entirely with candlelight, his face reading at 40 IRE at our “base” exposure of T/2 at ISO 400. The rest of the image was left to fall into darkness, except for a string of background lights. In each subsequent shot, we stopped down on the lens and increased the ISO to compensate for the exposure loss. Our goal was to track the noise level at increased ISOs as well as color and image fidelity in underexposure.

In this comparison, it is clear that the Helium is much cleaner at higher ISOs than the Alexa, but we found that the Alexa holds up surprisingly well and performed better than we expected. At 1600 ISO, the Alexa is still relatively clean; at 3200, the noise floor is plainly evident, especially when compared to the cleaner Helium image.

Interestingly, the RED image loses color detail when it is underexposed and re-balanced in the grade, whereas the Alexa footage retains all of its color detail in the lower-mid tone range of the image, even at higher ISO’s. You can see in the comparison above that the color fidelity in the subject’s face and the background of the scene changes from ISO 400 to ISO 3200 on the Helium sensor.

The visual and color details in the shadows on the Helium sensor seem to lose information sooner.

The rolloff into the shadows on the Alexa is more gradual as well; the visual and color details in the shadows on the Helium sensor seem to lose information sooner. From what we can tell, the Log3G10 gamma space clips information in the shadows. Therefore, when attempting to lift information out of the shadows in Log3G10, the information remains clipped, whereas Log-C on the Alexa re-interprets the information and is able to pull more visual and color detail out of the shadows when underexposure is “lifted” in the grade.

Test 3: Color fidelity

In this test, we set out to specifically check the color fidelity of the cameras and how closely they are able to match to colors in reality. We lit a brightly saturated scene using our Digital Sputnik DS-1 heads and set our initial exposure at T/2 and ISO 800, and stopped down incrementally to test color detail retention in underexposure. In the color grade, we matched the green and magenta tones in the background across both cameras, and let the other colors fall the way the cameras interpreted them.

The first and most obvious difference between the images is how the two cameras interpret the teal key light on the subject’s face. The Alexa leans towards the green end of the spectrum, which results in a much greener shade of teal. The RED, on the other hand, has a magenta lean, which results in a much bluer-looking key light.

A more subtle difference in interpretation between the cameras can be found in the color red: the Alexa has a lot more pink in its rendition of red, while the same color on Helium leans a bit more towards orange. Throughout our testing, we found that in general the Alexa Log-C to Rec709 LUT is far more aggressive with saturated colors than the IPP2 workflow, which favors more muted colors.

Test 4: "Natural" interiors

We wanted to set up a real-world lighting scenario that DPs find ourselves in often: a naturalistic and contrasty interior with a bright, over-exposed window, deep shadows, and mixed color temperatures. We shot the test on an overcast day and so had to place a 1x1 LED panel just outside the window in order to create a blown-out hotspot on the curtains in the background. This light also flared the lens a little bit, which we decided to embrace, as it fit with our goal of creating a “real world” testing scenario, warts and all.

In the shadow regions, the Alexa manages to retain more information and visual detail.

The rest of the scene was lit solely with the practical lamp on the coffee table, and with no fill light. Each subsequent shot was underexposed by a stop (our starting stop was a T/2) and the ISO lifted in the grade to compensate. We attempted to retain detail in the highlights as much as possible while lifting the mid tones in the image to see if we could find a spot in which the window and the foreground were both properly exposed.

This test served as a great summary of all the differences between these cameras for us. First, in the highlights, we found that the Alexa is able to retain more detail in the overexposed curtains than the Helium, and the rolloff is more gradual. At two stops underexposure, the curtains (which metered at a 32, +8 stops overexposure from middle gray) retain full detail on the Alexa, while they still show some clipping on the RED. At three stops underexposure, both cameras are able to retain full detail in the curtains. The lamp on the coffee table is also clipping in our base exposure (T/2) shot in the Helium footage, whereas the Alexa shot retains all highlight detail in the lamp.

In the shadow regions, the Alexa also manages to retain more information and visual detail, whereas the Helium clips information in the shadows. This is best demonstrated at the farthest extreme we tested—4 stops underexposure—where you can see in the comparison above that there is information loss in the cheeks and shadow regions of our subject’s face in the Helium footage. This can also be seen the darkest regions of the leather couch the subject is sitting on.

The Alexa footage has a green tint that differs greatly from the RED’s interpretation of daylight, which is a lot cooler and more neutral.

In the overall image, the Alexa footage has a green tint that differs greatly from the RED’s interpretation of daylight, which is a lot cooler and more neutral. The light emulating from the lamp is also a lot more saturated in the Alexa footage and results in more warmth in the subject’s skin tone as compared to the more muted Helium footage. Finally, worthy of note is how much cleaner the shadow regions are in the Helium footage compared to the Alexa footage.

Test 5: Available light at night

In our final test, we took the cameras out at night to shoot some uncontrolled available light and see how they interpreted some odd color temperatures that can be found on the street. Specifically, we wanted to see how the cameras handled sodium and mercury vapor lamps differently. Similar to our colored lights test, we noticed that the sodium vapor spectrum leaned more towards yellow in the RED footage, whereas on Alexa, it was a deeper orange. Additionally, the mercury vapor lighting looks greener on the Alexa, while the RED interprets it as a little more blue. Ultimately, we found both interpretations of mercury and sodium vapor interesting in their own way and both cameras performed well in uncontrolled lighting environments at night, with relatively clean images even at ISO 1600.

The ARRI Alexa Mini and the Red Epic-W equipped with Leica Summicron-C Lenses.

Final conclusions

All in all, we found this test quite illuminating. It reiterated things we knew from using these cameras in the field but also demonstrated many things we were surprised to learn about each of them.Namely, the Alexa has more latitude in the highlights (about 1.5 stops more dynamic range than the RED) and is able to retain more color detail through various degrees of over and under exposure. The RED has less noise in higher ISOs than the Alexa, and by our estimation has a significantly improved color fidelity when compared to previous RED sensors.

That being said, both of these cameras create viable images and are at the top of their technical game, and a preference of one over the other is purely subjective. Ultimately, they are just tools, and no one camera can substitute a DP’s artistic eye and taste for lighting and composition when it comes to creating a compelling image.

Feel free to draw your own conclusions by downloading our test footage from both cameras, as well as the stills from this article, at this link to our full resolution RAW files. Please note that in order to use the IPP2 Preview LUT, you need to select "Show Advanced Controls" in Red Cine X. The LUT can be downloaded here.

Charlie, Alex, Justin and Oren are all cinematographers based in New York City. Alan Gordon is a colorist with Post Pro Gumbo, also in New York. Their collaborators on this project included Frank Appolonio, Kyle Derry, and Amanda Markoya.

Yes - during the grade, we applied both RedLogFilm and LOG3G10 to the RED footage and noticed no difference in terms of highlight retention. The LOG3G10 space simply brings the overall exposure of the image down by about a stop compared to the Alexa (as you can see in our examples where we included LOG images), but it does not reveal any "new" information in the highlights that was not accessible prior to that.

Just a note that current IPP2 implementation actually fixes the highlight clipping seen in this test. I hope to see this footage redirected through the new RED algorithm for proper results. Some of the crew over on REDUser are already dispelling things:

This is a fantastic comparison, and mirrored a lot of what I found out when we did our own testing with the Helium, except we used a Sony F55 with AXS-R7 RAW recorder instead of the Alexa Mini. We definitely saw a lack of range in the highlights, and strange color shifts all across the board. Anyone interested in that test can find it here. http://zsyst.com/2017/02/f55-vs-red-helium-8k-vs-red-dragon-6k/
I think the Helium sensor will get much better as they develop better processing science for it instead of borrowing from the Dragon sensor.

Sony does a horrible job of marketing their brand for high end cinema work. The F5/55 are literally everywhere in the pro sports world and see a fair amount of work in television, but you see very few films shot on Sony because the name doesn't carry the same weight as Arri or RED.

As an owner of the Sony F65, Sony shot themselves in their own foot. The F65 I think is the best looking digital image of all time, yet the workflow and the battery usage and size of the beast and data rate ended its career in the high-end world. And it's a shame, cause the workflow now is super simple and it has a mechanical shutter!

This once again goes to show that it doesn't matter how much you spend on a camera package, your footage can still look like trash when being careless. There are reasons that big productions use the best gear, but it's never the tools, rather the intent, care and craft that deliver what captivate us. A helpful thought when I begin to drool over tech.

800 is not the native ISO for the Helium sensor. This test is flawed off the bat by not testing the Helium's Native ISO at 1280+.

Also, we all know that this sensor is brand new and still a work in progress. I'm not excusing that, but it's the truth. The Mini has been out for years, till the Helium color science has been launched, this comparison is pretty pointless.

The test is still very valid. This is not any indication of what this camera will do in a year, or five down the line. The sensor is shipping in camera and this is a pretty fair representation of what you can get today.

The tests were using the same lights setting and lenses. It's hard to argue with the transparency of this test.

There was nothing wrong at all with the performance of the Red in this test. It had different performance than than the ARRI, not worse. If the camera has radically different performance at 800 vs 1250 that would be alarming.

@ Emil Do you honestly think the head engineer of RED(who has a special interest in RED due to him being an employee and his investment of time, energy, and hard work) and guys in a facebook group called Epic- W are going to agree with the results of these tests? Have you noticed that every time a test is shown to display results favoring Arri's cameras compared to RED's, REDusers and RED employees ALWAYS say it wasn't done right? I'm not joking, like all the time. Even though comparison after comparison still shows the Alexa has the upper hand in image quality regarding Dynamic Range, skintones, color, etc. They weren't even comparing the Alexa SXT with the Helium, which to me is a fairer shootout due to both being the latest releases. I wouldn't go to RED forums or groups to get bipartisan opinions or factual results, just like I would not go to ARRI groups. That's like going to a Boston Red Sox bar, and asking the fans who is the best baseball team. I also wouldn't say the test was completely pointless....it's far from it. Radiant Images pretty much had similar results https://vimeo.com/140441330. But I mean, I'm sure you're pretty devoted to one of these companies ;D

We stand by the test. Both are cameras that are available for purchase and for use in the current market, and so we felt it was perfectly fair to test them in their current state, while of course mentioning the caveat right off the bat that the RED color science is currently unfinished and a work in progress.

As for the native ISO, we mention that this number for the RED camera is 1280, but bear in mind that at that ISO, the Alexa also gains an extra +2/3 stop of dynamic range in the highlights as well. If we had shot all of the footage at ISO 1280 including on the Alexa, the comparison and ratio of difference between the dynamic range of two sensors would be no different at that ISO.

This would have been the ideal set-up, yes, but unfortunately we didn't have time to shoot each lighting set-up separately on both cameras with different ISO's, so settled on one for simplicity.

That said, this is actually slightly incorrect logic. ISO doesn't work like a film stock - it's actually all relative. Both cameras' real ISO's is somewhere way lower - 400, 800, 1280, 1600... these are all varying degrees of artificial digital signal boosting in order for the sensor to be able to record more light. They're all relative.

And the "base ISO" of both cameras - 800 and 1280 - is relative as well: these are just the ISO's at which the dynamic range of the sensor is most evenly distributed in both the shadow and highlight range, from middle gray, and so is just the "ideal" ISO in order to capture the maximum range of tonality in the highlights and shadows.

Changing the ISO on either camera doesn't actually affect the DR - all it does is "shift" the Dynamic Range either towards the shadow region (if you lower ISO) or towards the highlight region (if you raise it). That's all it would do.

I'm in 100% agreement on all of that. Everything you just said confirms why you should rate the Helium for a higher ISO.

You shifted the DR away from the highlights on Helium and now everyone's takeaway from this test is that Helium has an objective "1.5 stops worse highlights" than Alexa, when you and I both know that's all relative due to the sliding scale that is DR.

I'm just saying that calling this a "shootout" leads the reader to think there's going to be a defined "winner." When really it's just a test for a single metric: dynamic range.

If you were going to do a full shootout, then this thing needs to be like an hour long and compare compression, color fidelity/accuracy, frame rates, resolution, ergonomics, workflow, etc. etc. etc.

Alexa will win a lot of areas, still, I'm sure. I don't need Helium to "win." I just don't agree with the methodology here.

I'm gonna start mathing here, so bear with me. Even if you grant that the Native ISO of the Helium is 1280 and not 800 (I won't say it isn't) and that the test over exposes the Helium, it only does so by around 2/3 of a stop. It is easy to see from the tests above that the Alexa recovered from +5 stops significantly better than the Helium recovered from +4 stops. That is a greater difference than the 2/3 stop due to ISO. That leads me to believe that even had the cameras been shot at the "native" ISO's, the Alexa would have still offered more latitude for over exposure.

Ha ha haaa.. this is what I came for! I came for the butthurt RED Fanboys lol. This is not an insult guys.. its a test. RED now knows that it has homework to do and probably they should give resolution a break and focus on the colour science and the appropriation of the camera's Dynamic Range.

That is not very helpful. There are very few resources available for people to understand imaging pipeline and camera design.

If someone in the community heard from trusted there are flaws in a camera test it's not helpful to call them "butthurt RED fanboys" Especially since they stayed in the realm of respectability and didn't disparage the DP's involved.

I did a brief comparison of the Alexa and VariCam LT (and helium) on YouTube. It's not scientific (nowhere near like this test), just a very generic comparison. VariCam holds up in dynamic range against the Alexa quite well - colors are different, but both very filmic. Color space on the VariCam is slightly wider. Rolloff is beautiful on both cameras. Helium was nice, too, but did clip in the highlights maybe a stop or more sooner whereas the Alexa and VariCam simply saw through and rolled off like film.

Many other factors affect apparent sharpness at 4k mastering there is little effect between shooting at 3.2k vs 4, 6 or 8k or a 4k presentation.

DP Steve Yedlin did a very nice presentation on that at Cameraimage called "
Steve Yedlin Seminar: On Image Acquisition and Pipeline for High-Resolution Exhibition" that clearly shows the effects or lack of effect of camera resolution on presentation resolution.

He showed acquisition from 2k to 13k for a 4k dcp presentation. It's really great to see all of the cameras side by side. Any professional cinema camera is perfectly acceptable for mastering in 4k with no loss in quality.

Please make sure that you are only judging sharpness based on the full resolution RAW files we provided. The stills in the article have gone through many levels of compression, first to 1080p ProRes footage and then to .png image files to be featured in the article. In a side by side full res comparison, the 8K RED footage is demonstrably sharper than the 3.4K Alexa footage, and at the very least has more detail when blown up to its full resolution.

And no, Aaron, no sharpening or any other additional effects were added to any of the footage besides the basic grade!

Interesting. Still not sure I understand. It's all relative isn't it? If both files were compressed to 1080p then .png wouldn't the apparent resolution decrease equally. If anything shouldn't the apparent resolution decrease less in the image that started with twice the amount of data?

Sort of -- but you'd only be able to notice a marginal difference. And even when looking at the images in their full size on your laptop, you won't be able to really see it. You need to see them in a larger venue to discern the difference.

I guess the baffling thing to me is I DO see a marked difference on my 27" screen and I'm talking more so in the video than with the photos. I completely understand not truly being able to see the detail and sharpness until viewing it on a larger screen, but it's relative and I'm NOT arguing that I DON'T see a difference(in which the statements about compression would make total sense). I'm saying that I DO see quite a difference and the lesser (not even 4k Cam seems to be resolving more detail than the 8K. Not that it matters much on the planet that I live on...I'm shooting on a GH4 :)

When it comes to cinema we do see much more Alexa but Netflix/Amazon Prime? Lots of RED because of the true 4k delivery. I think the Arri being up ressed to 4k looks great but for some reason they don't allow it.

Both of these cameras are amazing, but why does the Alexa look so much sharper than a camera with double the resolution? I’m confused… Also the Helium is supposed to have 2 more stops than the Alexa. I guess they are in the shadows? Is the Alexa DR underrated or is the Helium overrated. What am I missing here?

RED's DR has always been overrated since the marketing of the Dragon sensor. It isn't 16.5 + stops at all. Never was. It's pretty much like if they were telling customers they're going to get a V8 motor but it's actually V6. Alexa is 14.5 stops.

I completely agree - after we started the test we realized how much it would have been nice to also include a Dragon in the mix as well, to really demonstrate how the Helium differs from it, since all of us have shot on the Dragon before and were relatively familiar with what it was capable of doing. Next time!

Thank you for that comparison.
Unfortunately there seems to be a misconcept regarding the terminology of dynamic range vs. exposure latitude. You've proofed that the Alexa has 1,5 stops more exposure latitude than the Helium but don't mix that up with dynamic range because these are two different things.
"Dynamic range is the range the camera can see from the deepest darkest shadows to the brightest highlights in the same shot. Latitude is the range within the dynamic range where we can expose and still get a useable image."

Some people seem to be taking this as what camera is 'better' as opposed to a general guide of how they perform.

This test clearly shows how the cameras perform in controlled and reproduced situations. You can use this as a general guide on how to design your own tests.

Rating a camera isn't really set science as it was in film days when. In digital the sensor has a dynamic range, a clip point and a noise floor. Once you know how much light blows out the sensor, you need to make a decision on how much noise you can tolerate in your image. You noise tolerance sets the dynamic range. Then you pick how many stops of highlight(or shadow) you want and place your midgrey in the right place.

If you have a 1600 iso camera with 5 stops above midgrey and 5 below, and you decide you only want 3 stops of headroom, you now have a 400 iso camera. that camera now has 3 stops above midgrey, and 7 below.

I own a RED Helium Weapon and it doesn't have the dynamic range of an Alexa but I've found if you use the Truecolor RED to Alexa LUT you get a good starting point for color that gets it closer to the Alexa look (it will never be as good but its definitely an improvement). Also, you really have to expose to protect the highlights and you need to rate the camera at 1600iso. When I grade this footage, I'm always surprised about how much you can dig out of the shadows. Link to LUT below. It costs money but it was worth every penny to me. I tried to make my own RED to Alexa LUT and I could never get it as precise as this one.

I'm also finding that the resolving power of this camera is definitely a whole other beast. I've been shooting a couple of scenes at F22 on my Leica R's and you see a whole other world of detail that I've never seen before. I like deep focus so its something I appreciate about this camera. You need good lenses on this sensor because its a lot less forgiving of any flaws the lenses have.

I think someone else should do a test - with both cameras at their native resolution - RED at 1250 ASA and Alexa at 800 ASA to test dynamic range. At 800 ISO, if the red helium is already more usable in the shadows, that gives it more stops in dynamic range below key, and then imagine it at 1250 ASA!! I imagine it will pick up at least a stop of usable dynamic range in the highlights and still keep exposure in the shadows - and become a very useful tool.

Having a clean low-noise 1250 ISO camera is a very useful camera for small productions, for low-light night work.

I would be more interested in real-world night-testing with this said.

In terms of color fidelity and skintone - just from watching the video - I think the red is the winner.

But in terms of inherent resolution and motion cadence, the red for me is the winner.

All of this is subjective. And, also, for the record, I was banned from REDUSER.net TWICE.

Oy vey! I have read literally hundreds of threads on REDUSER.net which begin with complaints about dynamic range, high light clipping, noise in shadows, color fidelity, color shifts, etc., etc., and virtually all of them, when R3D files are finally posted an evaluated, point to a fundamental error in initial exposure. So when I read this

"In our testing, we found that the Helium’s native ISO was probably closer to
ISO 1280, but decided to match both cameras to 800 for the ease of
comparison."

I braced for the worst. This so-called test delivers exactly what I expected from any test that begins with such a fundamental error.

I really love the way the RAW workflow works. I really love the color and quality of the new RWG/Log3G10 combo. But if you start a test on the completely wrong foot, all conclusions are going to be misleading. I would suggest starting over and beginning as Phil Holland and others have done, by measuring the point at which midtone gray is in the middle of the DR chart (hint: it's not ISO 800 for Helium with the STD OLPF), use *that* as the base ISO, and then proceed from there.

Alexa makes an amazing camera. And it cards very well at ISO 800. Helium is a different beast and should be measured according to its baseline, not ISO 800.

This test is a bit flawed, i own both a Epic-W and have Sony cameras, RAW as well, tools for the job in hand. I love the Sony RAW images and the Red too.

You can't rate the helium at 800 iso, you need to rate both cameras at their native ISO otherwise it's just not a valid comparison. The helium is more sensitive, if you want to match exposure stop the lens down.

Then with the footage keep it RAW and then into linear space and actually compare image to image, data to data - keep it simple. Using LogC to 709 LUTs is another step where differences can happen. That 3D LUT could even be bringing highlights back (i.e. if Arri knows the clip point of a channel then it can use a 3D LUT to mix back other channels - i'm not saying they are but they could and it would be valid). But you could do that with Red too. There are so many points in a pipeline where clipping can happen erroneously.

So to make sweeping comments you really need to test bare bones like for like otherwise it's not fair on either camera.

It's also valid to test a camera in the way that you personally choose to use it, but the results aren't definitive then, they're a combination of camera, taste and workflow and everyone works differently. It's not quantative.

I appreciate these tests usual degenerate into fan-boism, but it is possible to test side by side in linear - which is the only valid quantitive result, assuming point of capture is fair for both.

Thank you for the great test! Even taking any minor exposure discrepancies into account, the differences are pretty clear. Very useful! I'd love to see the same test applied to the Panasonic VariCam LT, Canon C700, and even the Canon C300 mk II. Throw in a Sony F55 and an BM Ursa Mini 4.6K for good measure. The C700 was intentionally engineered to have a look similar to the Alexa, especially in highlight roll-off, in order to break into the Netflix, etc., markets. Would be great to know the differences.

I shared our comparison test between the Helium, Dragon and F55 in a link in the second comment to the thread. You can check that out. It's really hard to get all those cameras in the same place to do tests, and its very time consuming.

As far as the difference between Dynamic Range vs Exposure Latitude, for most working cinematographers, I think they are one in the same. I've never been too concerned about how many chips I can see, in as much how much information I can retain and manipulate.

That being said, I have seen the work of others and have personally been able to produce images I am very pleased with on BOTH systems. Tests like these simply help me to maximize the capabilities of each system.

Would someone please do a test of the RED Helium at 1250 iso! Can't wait for the next reasons why the test was invalid. (I.E. didn't properly color correct the footage, compression ratio was too high, you need to use the new red colored mini mags, the lens is to blame, back focus was not done well, you need to put it in a HDR-X mode, they didn't use REDCine-X Pro, you needed a Red Rocket, you have to use the Skintone-highlight olpf then switch it to lowlight olpf when you shoot at night, your lighting set up is completely wrong, your color temperature wasn't 3274, the camera is actually native 1600 ISO(folks on reduser are saying that now http://www.reduser.net/forum/showthread.php?154944-New-Epic-W-vs-Alexa-M...), you're using MAC instead of windows, the LUT you used wasn't meant for the Helium's advanced sensor, you're using the wrong codec for vimeo, the sensor is still in beta and hasn't achieved it's final Super Saiyan form, etc. Trust me, get ready to hear it all. They're already redvising the results on the forum

The real problem could simply be the LUT. I've given up on LUTs because they often do wonky things to images, clipping highs and lows, weird curves, colors, etc. The difference between 800 and 1250 is a 1/2 stop. not enough to account for the RED's problems. FAR more likely the LUT used is the problem. I'd highly suggest instead doing a hand grade begining with taking white to white, black to black, and a hand dialed in curve as a base grade and see what you get. Far easier to get a good image that way in which you can control things. Having had LUTs trash images - clipping in particular, I've simple lost patience in dealing with them for grading and bring out the most the captured image has to offer.

Yes it would of been great to throw in a F5 and C300 mk2 into the mix as this pretty much the go to cameras these days depending on what sort of productions you work on

I did attempt to hand grade the Helium footage in our test and it clipped at the same point. I also tried grading off of a Croma DuMonde with no luck. I won't go so far as to say that the sensor doesn't have the capacity, I would lay the blame at the "beta" science behind the sensor, probably get fixed in the coming weeks or months. The Dragon in our test did much better.

thanks for that... I guess time will tell if RED does / can fix things. However if you have to go out and shoot something tomorrow morning... a fix down the road won't do you much good.

FWIW it took canon a good 6+ months to resolve shadow noise / horizontal banding / black sun in the C300 Mk2 but they did indeed improve it significantly, along with cLog3 which doesn't over stretch the shadows so much which brings up the noise floor. However even cLog2 looks better after firmer 1.03 but clog3 is probably the ideal setting to shoot with as its very easy to grade.

you can get the same performance from the pre 1.0.3 as the after. The noise correction and chroma noise reduction was turned off by default. Turning it on makes a big difference in performance.

Clog2 seems hold more dynamic range than clog3 but as you said, it is easier to grade. It's close enough to ARRILog C you can put an arri lut on Clog3 material and tune in a hue adjust, saturation adjustment and pretty much rock and roll.

Yes - like any digital sensor, the Helium gains exposure latitude in the highlights as you increase ISO, and loses latitude in the shadows. Between 800ISO and 1600ISO the DR will "shift" towards the highlights by one stop. The Alexa does this as well - exposure latitude extends to being able to retain +6 stops overexposure in highlights at 1600ISO, up of +5 at 800!

Thanks for this test. Some here say it's invalid as the Red was rated at 800 instead of 1250. I have to disagree. Most of the scenes were low key scenes, especially at the beginning. In this case, half a stop over, should benefit from the increased floor and reduced noise for the many night scenes. Though you may lose some color depth on the key side of white skin. Overall, to me the helium is not the breakthrough it's being touted as. It still has less depth to the skin tones than the Arri. I find the mini just has a more nuanced and natural tonal range.

All this said, I'd love to see just a simple A/B test with the Red at 1250 and the Alexa at 800. Just a key, a color chart and a hot highlight. I know doing tests right takes time and allows for few mistakes. So if you do go back to the drawing board, go simple and just give us native ISO +/- 1,2,3 stops in under tungsten then daylight.

While, I still suspect the Arri will produce a more detailed and richer image, it's also worth noting other aspects of an Arri vs Red test, such as usability. I personally find the Arri a piece of cake with its Fisher Price knobs, far less complicated than Red's menu set. Also, there's the built in ND's.

What?
It seems that this article is done by people who have never used a Red. If they had used a Low Light OLPF what would happen?
Is It possible that people do not see the difference between a Helium RED 8k ($30k) and a ARRI Mini ($40k) that just arrive to 4k? Red is a perfect CAMERA and without limits!
I wish you could see the difference at comparable Grading between both MDP and judge with your eyes. I do trust #nofilmschool but this article is ridiculous!

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